import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;
public class BounceBall{
public static void main(String[] args) {
JFrame frame = new BounceFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOS E);
frame.setVisible(true);
}
}
class BounceFrame extends JFrame {
private BallCanvas canvas;
public static final int WIDTH = 450;
public static final int HEIGHT = 350;
public BounceFrame() {
setSize(WIDTH, HEIGHT);
setTitle("BounceThread");
Container contentPane = getContentPane();
canvas = new BallCanvas();
contentPane.add(canvas, BorderLayout.CENTER);
JPanel buttonPanel = new JPanel();
addButton(buttonPanel, "Add Ball",
new ActionListener() {
public void actionPerformed(ActionEvent evt) {
addBall();
}
});
addButton(buttonPanel, "Exit",
new ActionListener() {
public void actionPerformed(ActionEvent evt) {
System.exit(0);
}
class BallThread extends Thread {
private BouncingBall b;
public BallThread(BouncingBall aBall) { b = aBall; }
public void run() {
try {
for (int i = 1; i <= 1000; i++) {
b.move();
sleep(5);
}
} catch (InterruptedException exception) {
}
}
}
class BallCanvas extends JPanel {
private ArrayList balls = new ArrayList();
public void add(BouncingBall b) {
balls.add(b);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
for (int i = 0; i < balls.size(); i++) {
BouncingBall b = (BouncingBall)balls.get(i);
b.draw(g2);
}
}
}
class BouncingBall {
private Component canvas;
private static final int XSIZE = 15;
private static final int YSIZE = 15;
private int x = 0;
private int y = 0;
private int dx = 2;
private int dy = 2;
public BouncingBall(Component c) { canvas = c; }
Color color = getColor();
public void draw(Graphics2D g2) {
g2.setColor(color);
g2.fillOval(x,y,30,30); // adds color to circle
g2.drawOval(x,y,30,30); // draws circle
}
public void move() {
x += dx;
y += dy;
if (x < 0) {
x = 0;
dx = -dx;
}
if (x + XSIZE >= canvas.getWidth()) {
x = canvas.getWidth() - XSIZE;
dx = -dx;
}
if (y < 0) {
y = 0;
dy = -dy;
}
if (y + YSIZE >= canvas.getHeight()) {
y = canvas.getHeight() - YSIZE;
dy = -dy;
}
canvas.repaint();
}
private Color getColor() {
int rval = (int)Math.floor(Math.random() * 256);
int gval = (int)Math.floor(Math.random() * 256);
int bval = (int)Math.floor(Math.random() * 256);
return new Color(rval, gval, bval);
}
}